| 1. |
- Moles, A. T., et al.
(författare)
-
Putting plant resistance traits on the map : A test of the idea that plants are better defended at lower latitudes
- 2011
-
Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 191:3, s. 777-788
-
Tidskriftsartikel (refereegranskat)abstract
- It has long been believed that plant species from the tropics have higher levels of traits associated with resistance to herbivores than do species from higher latitudes. A meta-analysis recently showed that the published literature does not support this theory. However, the idea has never been tested using data gathered with consistent methods from a wide range of latitudes. • We quantified the relationship between latitude and a broad range of chemical and physical traits across 301 species from 75 sites world-wide. • Six putative resistance traits, including tannins, the concentration of lipids (an indicator of oils, waxes and resins), and leaf toughness were greater in high-latitude species. Six traits, including cyanide production and the presence of spines, were unrelated to latitude. Only ash content (an indicator of inorganic substances such as calcium oxalates and phytoliths) and the properties of species with delayed greening were higher in the tropics. • Our results do not support the hypothesis that tropical plants have higher levels of resistance traits than do plants from higher latitudes. If anything, plants have higher resistance toward the poles. The greater resistance traits of high-latitude species might be explained by the greater cost of losing a given amount of leaf tissue in low-productivity environments. © 2011 New Phytologist Trust.
|
|
| 2. |
- Moles, Angela T, et al.
(författare)
-
Correlations between physical and chemical defences in plants : tradeoffs, syndromes, or just many different ways to skin a herbivorous cat?
- 2013
-
Ingår i: New Phytologist. - : Wiley-Blackwell. - 0028-646X .- 1469-8137. ; 198:1, s. 252-263
-
Tidskriftsartikel (refereegranskat)abstract
- Most plant species have a range of traits that deter herbivores. However, understanding of how different defences are related to one another is surprisingly weak. Many authors argue that defence traits trade off against one another, while others argue that they form coordinated defence syndromes. We collected a dataset of unprecedented taxonomic and geographic scope (261 species spanning 80 families, from 75 sites across the globe) to investigate relationships among four chemical and six physical defences. Five of the 45 pairwise correlations between defence traits were significant and three of these were tradeoffs. The relationship between species' overall chemical and physical defence levels was marginally nonsignificant (P=0.08), and remained nonsignificant after accounting for phylogeny, growth form and abundance. Neither categorical principal component analysis (PCA) nor hierarchical cluster analysis supported the idea that species displayed defence syndromes. Our results do not support arguments for tradeoffs or for coordinated defence syndromes. Rather, plants display a range of combinations of defence traits. We suggest this lack of consistent defence syndromes may be adaptive, resulting from selective pressure to deploy a different combination of defences to coexisting species.
|
|
| 3. |
|
|
| 4. |
- Unger, B., et al.
(författare)
-
MiniSCANS-II: Aerial survey for harbour porpoises in the western Baltic Sea, Belt Sea, the Sound and Kattegat in 2020 : Joint survey by Denmark, Germany and Sweden. Final report to Danish Environmental Protection Agency, German Federal Agency for Nature Conservation and Swedish Agency for Marine and Water Management.
- 2021
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The Marine Strategy Framework Directive (MSFD) (Directive 2008/56/EC) emphasises the need for cross-border monitoring of wide-ranging species, such as the harbour porpoise (Phocoena phocoena), the most abundant cetacean species occurring year-round in the Baltic Sea. In June and July 2020, Germany, Denmark, and Sweden conducted a dedicated large-scale aerial survey (called MiniSCANS-II) for harbour porpoises in the management area of the Belt Sea population, i.e., between an east-west line between Denmark and Sweden at 56.95°N in the Kattegat Sea, and a north-south line between Sweden and Germany at 13.5°E in the southern Baltic Sea. This survey followed line-transect distance sampling methodology according to the SCANS protocol to derive an unbiased absolute abundance estimate. With a realised effort of 4,533 km in nine strata, the observers recorded a total of 202 sightings (251 individuals, of these 16 were calves). The large majority of survey effort (91.2%) was conducted in either good or moderate sighting conditions. The abundance of the Belt Sea population was estimated to be 17,301 harbour porpoises (95% CI = 11,695-25,688; CV = 0.20), with an average density of 0.41 individuals/km² (95% CI = 0.28-0.61). This is the lowest abundance estimate since the first (SCANS) survey was conducted in 1994. However, the variance (especially of the earlier abundance estimates) is high, and a dedicated trend analysis needs to be conducted to determine if there has been a decline in the population abundance over time. The results should raise some concern about the status of the population and emphasise the importance of repeated surveys in the near future to increase the time series of robust abundance estimates available. Such time series are essential for monitoring the progress of the population towards achieving favourable conservation status under the Habitats Directive and good environmental status (GES) as demanded by the MSFD.
|
|
